A panoply of efforts have been purported to affect materials by high-pressure compression. Exemplary of the techniques having been established include the use of diamond anvil technology for the compression of molecular solid hydrogen above 3 megabars. The process was useful in terms of generating a significant density increase and phase transformations. This work was further augmented by others where solid nitrogen was compressed into the megabar range where it was then observed to provide a semi-conducting polymeric phase. Two-stage light gas gun technology has been employed as an alternative approach to pursue compression of liquid hydrogen into the megabar range where the hydrogen becomes conductive. These techniques are limited to the observation of very small samples in several to tens of micrometers at megabar pressures.
In terms of the parallel contemporary progress in this field, compression of large samples has been achieved most recently using explosive based cylindrical methods. These processes, when unified, have also produced extremely high pressures in materials.
In the prior art, general attempts to provide shaped charge arrangements have been demonstrated. One example is that which is illustrated in the Barnes U.S. Pat. No. 2,984,307. The Barnes reference teaches an annular shaped charge effect focusing at a location out of the apparatus body. Accordingly, the structure of the apparatus is incapable of providing detonation in a super-compressed insensitive energetic material within the body of the apparatus.
In the Barnes arrangement, the device is structured to be a housing for hosting an annular explosive that provides the power for the cavity effect of the shaped charge focusing on the position out of the apparatus body. The structure of the housing and the encased explosive together with the entire structure of the apparatus cannot form a precisely controlled normal or oblique detonation wave, which is most desirable for imploding compression applications, even if an anvil surrounded by explosive material were added at the center of the apparatus.
In the drawings of the Barnes arrangement, element 30 is simply a further version of the housing replacing housing 10 to host the annular explosive for the same shaped charge effect with a slightly different cross-section to reduce hosted explosive mass indicated by numeral 34. This is structured to be the replacement of explosive 12, not surrounded by explosive 12. There is no means for housing 30 to be used as a sample anvil.
It was subsequently discovered that a cylindrical metal liner could be imploded by an explosive to compress the magnetic flux in the annular gap between a liner and sample tube. It was determined that by increasing the magnetic field, the metal sample tube was compressed which, in turn, isentropically compressed the hydrogen fluid contained in the sample tube. Radiography was employed to determine diameter changes and by this technology, it was observed that the hydrogen density was increased fourteen-fold. Further compression systems employing explosive implosion devices without magnetic flux have also advanced the art.
One of the most common features to such arrangement is that the implosion generally occurs simultaneously along the length of the sample and is driven by a converging detonation wave propagating at a direction normal to and toward the axis.
In contrast, other conducted studies of cylindrical implosion of a sample have been set forth in which a Chapman-Jouguet (CJ) detonation propagating through an explosive parallel to the axis compresses the sample in an axially sequential fashion. When these latter implosion systems are compared with those driven by radially propagating detonation, they are found to be easier to implement, but result in lower compression. Between the two limits of an explosive detonation propagating normally to the axis and that propagating parallel to the axis, there exist cylindrical compression systems driven by oblique explosive detonation propagating at an angle to the axis as discussed by Zerwekh et al. (Zerwekh, W. D., Marsh, S. P. and Tan T.-H., AIP Conference Proceedings 309:1877-1880, 1994). They developed a phased shock tube system, in which a cylindrical steel flyer was explosively propelled inward and impinged on a conical aluminum-phasing lens. This initiated an oblique detonation wave in a cylindrical shell of high explosive and resulted in a Mach disk shock propagating in an axial cylinder of foamed polystyrene sample. The device functioned like a shock tube and the Mach disk shock created has been employed to propel a 1.5 mm thick steel disk above 10 km/s. Recently, Carton et al. employed a two-layer explosive configuration to obtain an oblique detonation wave, whose angle is determined by the ratio of the fast detonation velocity of the outer explosive over the slow detonation velocity of the inner explosive (Carton, E. P., Verbeek, H. J, Stuivinga, M. and Schoomnan, J., J. Appl. Phys. 81:3038-3045, 1997). This device has been used for dynamic compaction of powders and the axial compaction wave velocity is limited to the CJ detonation velocity of the outer explosive.
In summary, recent high-pressure compression technologies have been successful in achieving dynamic compaction of powders or compressing a molecular liquid to a super-dense fluid, whose density is several-fold the initial density with structural phase transformations, electronic energy-gap closing and the presence of atomic particles. The cylindrical explosive implosion technologies have been developed to compress materials and mainly operated in two generic driving modes: explosive converging detonation propagating in a direction normal to and towards the axis, or explosive CJ detonation propagating parallel to the axis.
Efforts have also been purported to ignite thermonuclear explosions by explosive implosion techniques.
Methods and technologies have not been developed for detonation of super-compressed, conventional reactive materials to alter the detonation velocity and pressure. Super-compression means a pressure level of close to or above the range of one megabar.
Generally, the effectiveness of munitions involving detonation of explosive materials largely depends on the detonation velocity and pressure in the explosion phase of the detonation. Existing technologies deliver detonation velocities and pressures in the range of a few kilometres per second and several hundred kilobars, respectively.